The present invention relates to a pipe cleaning nozzle for the cleaning of pipe conduits, particularly of pipe conduits in toilet systems of aircraft, by use of a pressurized cleaning jet.
Pipe conduits for sanitary waste water tend to become soiled by impurities and deposits of urinary sediments which considerably affect the functioning of the toilet system. Thus, pipe conduits of the above type have to be cleaned in certain intervals. German Patent 197 03 317 A1 describes a pipe cleaning nozzle which is subjected to a pressure of about 400 bar to 420 bar. The nozzle orifices, directed toward the outside, are configured to eject pressurized jets with high kinetic energy to destroy and wash off the impurities attached to the pipe wall. The pipe cleaning nozzle comprises a nozzle head which is by a few millimeters smaller than the free cross section of the pipe so that the pressurized jets will impinge on the deposits with high energy. The pressurized jets, largely oriented in radial directions, have rearward axial component provided to generate the advance movement of the nozzle head in the pipe conduit. In this manner, the nozzle head will move through the pipe conduit to be cleaned, while taking along the high-pressure hose connected thereto for supply of the cleaning liquid.
Aboard aircraft, ships or trains, the toilet pipes connected to a vacuum source have diameters in the range of 50 mm. These toilet pipes can have a length of 70 to 100 m, and their course has to follow small-radiused bends and curves. Further, such pipes conduits include portions where the pipes are guided horizontally or vertically. Cleaning work to be carried out on such pipes is extremely difficult.
It is an object of the invention to provide a cleaning nozzle which is suited particularly for the cleaning of vacuum toilet pipes which have a small cross section and have been laid to follow narrow curves.
The cleaning nozzle according to the instant invention comprises a concave rear wall having its deepened portion provided with the connector piece for the high-pressure hose. Thus, the nozzle head has an extremely short constructional length. A part of the length of the connector piece has been sunk, as it were, into the nozzle head so that the overall length of the combined nozzle head and connector piece can be kept short. Since the connector piece and the nozzle head form a rigid unit, the length of this unit will determine the smallest radius of curvature of the pipe that would still allow the passage of the cleaning unit. The outer diameter of the nozzle head is about twice as large as the outer diameter of the connector piece, so that, on the one hand, the nozzle orifices will come close to the pipe wall while, on the other hand, the connector piece can be given the smallest possible diameter.
Preferably, the nozzle head has a convex front wall. The convex front wall and the concave rear wall together have a shape similar to that of a mushroom head. Arranged inside the nozzle head is the distributor chamber for the pressurized fluid while the nozzle orifices are arranged on a circumferential portion which has a relatively large diameter as compared to the diameter of the connector piece.
Preferably, the front wall and/or the rear wall are formed as spherical shells.
The instant invention further relates to a method for the cleaning of pipe conduits by use of a pipe cleaning nozzle comprising a connector piece and nozzle orifices, with the nozzle orifices directed radially outwards and having an axial component oriented in the direction of the connector piece. According to a characteristic aspect of the instant method, that pipe portion which is facing away from the connector piece, is connected to a suction source for the removal of detached deposits. This means that the cleaning jets are discharged from the nozzle head with a rearward component while the suction source performs the suctional removal in the forward direction. The term xe2x80x9cforwardxe2x80x9d in the present context is meant to denote the moving direction of the pipe cleaning nozzle during the advance movement, wherein the advance movement is generated by the recoil effect of the discharged cleaning jets. The mixture of cleaning liquid and deposits is positively drained in the direction opposite to the direction of the detachment.
An embodiment of the invention will be described in greater detail hereunder with reference to the drawings.